The original music is quite nice on its own merit but I don't think it always fits the situation at hand, could do with having a more frantic feel to it.
the collision with the fire seemed a bit off, by which I mean I thought jumping after hitting the wall underneath a fire would be safe enough but collides on the way up even though the fire doesnt visually extend past that vertical line.
Presentation's quite nice, though there were times where I'd keep restarting the level knowing what upgrades I needed and the wall was still falling down behind the character by the time I was ready which caused a tiny bit of frustration, particularly when coupled with the tight time frames of the later levels themselves where even if you have the proper upgrades figured out a mis-input will cause a loss.